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Marine Science

Senior Theses 2008

Kelli Hoover (2008) Holocene climate and hydrologic variability as recorded in the benthic foraminifera Ammonia beccarii from Tampa Bay, FL

Faculty Advisor: David Hastings

This study focuses on the climate and hydrologic variability of Tampa Bay, Florida over the Holocene epoch. Oxygen isotopic ratios and Mg/Ca data from the benthic foraminifera Ammonia beccarii in sediment cores provide records of the temperature and salinity changes in Tampa Bay over the last 10,000 years. A temperature reconstruction using Mg/Ca presents evidence for the correlation of Tampa Bay climate with other North American regions.

The highest temperatures within this record occur from 1000-700 yr BP, which correlates with the commonly accepted timing of the Medieval Warm Period. The lowest temperatures within the most recent 500 years occur from 450-150 yr BP, correlating with the timing of the Little Ice Age. This record shows that relative temperatures have increased by approximately 3-4°C from 500 yr BP to present.

Oxygen isotopic ratios provide evidence for significant changes to the hydrology of Tampa Bay. The signals of d18Oseawater are poorly correlated among the three sites, indicating that forcings other than temperature and salinity are influencing the environmental chemistry of Tampa Bay during the Holocene. This study provides the first climate reconstruction of Tampa Bay, FL over the last 10,000 years.